Moody's said late Tuesday it made the one notch downgrade to noninvestment territory because it sees a high risk of Ireland needing a second bailout at the end of 2013 when the country is supposed to have weaned itself off its EU and International Monetary Fund €67.5 billion $94.34 billion aid program.

This may involve selecting women employed in noninvestment banking positions, or who are currently insufficiently senior, but who show sufficient potential to be selected and trained for more high-powered roles, the headhunters say.

"Market participants have already factored in a one-notch downgrade for Nomura, so unless Moody's lowers it by two notches to noninvestment grade, it won't affect its share price negatively," one analyst said.